meta-analysis of the effectiveness of cctv systems › files ›...

meta-analysis of the effectiveness

of cctv systems

lucas melgaço vrije universiteit brussel

Melgaço L., Verfaillie K., Hildebrandt M. (2013)

CCTV and Smart CCTV effectiveness: a meta-level analysis.

SIAM - Security Impact Assessment Measures

complexity simplicity

“Rationality is a game, the perpetual dialogue between our spirit, that creates logical structures,

implementing them to the world and which dialogues with this real world.”

(Morin, Introduction à la pensée complexe, 2005)

rationalization

efficiency

calculability

predictability

control

rationalization of spaces

cctv as rationalization calculability (the quantification of the number of persons or objects present in a scene) efficiency (police officers may be better deployed) control (intervention in actions that scape normality) predictability (one may assume that actions taken in a monitored space tend to be more predictable)

complexities involved in measuring effectiveness of cctv systems

changes in patterns of crime reporting and recording

efficiency vs effectiveness

costs

fear and safety feelings

pseudo-random fluctuations in crime rates and floor effects

displacement - diffusion of benefits

cctv as part of a package of crime prevention measures

“Across the six camera locations covered in the study,

the number of crimes recorded by the police before the installation of CCTV was 205,

and the number of crimes recorded by the police after the installation of CCTV was 213.”

(Justice Analytical Services, The Effectiveness of Public Space CCTV, 2009))




costs





“There will rarely if ever be sufficient data to assess the full costs and benefits that can be directly attributable to CCTV.

The potential choice of what to include as a cost and a benefit is so wide that robust and meaningful estimates will

seldom be possible.”

(Tilley, Evaluating the Effectiveness of CCTV Schemes, 1998)




costs





"CCTV is not making the unsafe feel safe, it is making the already safe feel safer”

(Ditton, Crime and the City, 2000)




costs





CCTV systems +

police patrol improved lighting

installation of passenger alarms notices and signs about CCTV

past = investigation present = detection future = deterrence

I would argue that CCTV is generally ineffective as a crime

prevention tool. This is because the cameras, in these examples, are clearly not producing “anticipatory conformity” in the

population, deterring criminals, nor are they offering Big Brother protection to those under their gaze. Their use, in this type of

scenario, is limited to the reconstruction of events for post crime police enquiries.

(Smith, Behind the Screens, 2004)

video surveillance seems to be more effective within the first year following the installation but such deterrence effects usually fade with time one of the reasons for this being the fact that media play a role in publicizing the CCTV installation

(Griffiths, Town centre CCTV, 2003)

while the “past” and the “present” functions of video surveillance may keep up the same degree of effectiveness

over time, the “future” function has an expiry date

the more complex a situation or a space is,

the larger the number of variables to be considered; hence, more challenging the rationalisation process

cctv systems appear to be significantly effective in reducing

crimes in less complex settings, such as parking lots

(Webb and Laycock, 1992; Armitage, 2002; Griffiths, 2003; Carli, 2008; Welsh and Farrington, 2009).

“CCTV is most effective in reducing crime in car parks,

is most effective in reducing vehicle crimes, and is more effective in reducing crime in the UK than in other

countries.”

(Welsh and Farrington, Closed-circuit television surveillance and crime prevention, 2007)

“Recent research has resulted in evidence consistent with the

repeated finding that CCTV may be more effective in deterring crime in smaller and less complex areas than large city centres.”

(Justice Analytical Services, The Effectiveness of Public Space CCTV, 2009)

CCTV was most effective in reducing crime in car parks. It had no effect on violent crimes but had a significant desirable effect on vehicle crimes. (Welsh and Farrington, Effects of Closed-Circuit Television on Crime, 2002)

mixed findings from evaluation studies can often be expected simply because many pieces of work are technically flawed

or technically different,

they are also inevitable because measures will have differing impacts depending on the conditions in which they are

introduced.

This means that the frequently asked question, ‘Does CCTV work?’ admits and can admit of no consistent answer.

(Tilley, Evaluating the Effectiveness of CCTV Schemes, 1998).

“The ‘effectiveness’ of CCTV must be considered in light of its

intended purpose, as each individual project is installed to serve its own purpose.”

(Justice Analytical Services, The Effectiveness of Public Space CCTV, 2009)

crime rates may be a poor measure of the effectiveness

of CCTV interventions

(Gill and Spriggs, Assessing the impact of CCTV, 2005)

less complex a situation or a space is, the more effective cctv systems may be in reducing crime, and the more precise the

evaluation of such effectiveness will be

[email protected] @lucas_melgaco

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